Computer systems today strive for "user friendliness." Through simpler, more clearly explained displays and easier-to-use interfaces, designers attempt to make a system understandable for both an expert and a first time user. Designers developed touch screen displays from this desire for user friendly systems. Touch screen displays comprise a display surface on which an operator can selectively display information or perform a function by touching an icon displayed on the screen in an interactive manner. The touch screen is operatively connected to a microprocessor which stores, computes, and supplies information required or functions to perform. Several touch screen displays and their applications are described in the following patents: U.S. Pat. No. 5,737,729 to Denman (Apr. 7, 1998), U.S. Pat. No. 5,717,433 to Doba (Feb. 10, 1998), U.S. Pat. No. 5,572,573 to Sylvan (Nov. 5, 1996), U.S. Pat. No. 5,481,250 to Hano (Jan. 2, 1996), and U.S. Pat. No. 5,457,636 to Sansone (Oct. 10, 1995).
A kiosk, or small stand, is used for merchandising or vending services or goods, or for accessing information. Kiosks are well known in the art as indicated by the following U.S. Pat. No. 4,179,723 to Spencer (Dec. 18, 1979), U.S. Pat. No. 4,265,059 Johnson (May 5, 1981), U.S. Pat. No. 4,817,043 to Brown (Mar. 28, 1989), and U.S. Pat. No. 5,271,669 to Pearlson (Dec. 21, 1993). One advantage of a kiosk is that it can be provided in public areas and be used by many operators because of the simple, secure system provided in conjunction with the kiosk. Kiosks often include a microprocessor and visual display or monitor for interaction with the operator. This interaction is generally simple and allows an operator to step through several preset options by typing basic commands on a keyboard or selecting the options on a touch screen interface which perform internal functions such as calculations or displaying information, distributing merchandise or money, or if associated with a printing device and paper source, printing an output.
Touch screens are currently used in many commercial and noncommercial fields including industrial control systems such as plant and process controls, commercial control systems such as typical kiosk systems used with postal, photo, copy center, video phone, hospitals, and ATM systems, information kiosks such as those used in many tourist areas, libraries and restaurants, and many other systems where simple operator-interactive means are needed. Many systems also combine touch screens with other interface systems such as numeric or alphanumeric key pads (e.g., ATMs), and other more simple function keys. Although touch screen systems, as they exist, function adequately, there are a number of inadequacies. First, touch screen displays are relatively expensive. A typical touch screen display costs more than a non-touch screen display.
Second, because the screen of a touch screen display needs to be touched to activate it and because touch screens give off heat, touch screens are not easy to completely seal from the environment. This drawback may become significant when the display needs to be used in an area where it will be subjected to dust, chemical or bacterial contamination, or where the risk of contact with moisture is high. Because the system is not completely sealed and insulated from its surroundings, careful, thorough cleaning methods are applied, and the risk exists that contamination will damage the internal components of the device or come in contact with a subsequent user.
Third, once the screen is touched, the operator must wait for the computer to indicate the operator pressed hard enough and long enough for the touch screen to register the selection. Depending on how busy the system's processes are, this passage of time can be almost instantaneous, or can take some time. Often this delay frustrates users who make a selection which the processor does not register and indicate fast enough and they inadvertently make a second undesired selection by pressing again.
It would be advantageous to have a device as user friendly as a touch screen which is inexpensive, sealed to contamination, easily washable, and provides immediate feedback when an operator makes a selection.
User friendly input devices for computers are well known in the art. One of the several types of input devices is the familiar "mouse." When combined with a graphical user interface, a mouse can be much easier to use than typed keyboard commands. By moving the mouse across a surface, an operator causes a cursor to move correspondingly on a display screen. The mouse has been accepted as a "user friendly" input device for both experienced and novice computer users providing a simple means to interact with a computer. However, mice are disadvantageous in many applications because they generally require a free-rolling surface, e.g., a table top, on which to operate. Thus, a mouse is not well suited for use in confined spaces, or where little or no surface space exists such as with a kiosk or other touch screen application. A mouse also includes mechanical parts which can become jammed, dirty or worn, and generally cannot be sealed from outside contamination.
In answer to the long existing need for a more convenient input device suitable for all space requirements, limited or not, various alternative input devices have been proposed. These alternative input devices include devices commonly referred to as track balls, track pens and track point devices, as well as various devices which sense the position of a pointing object on a position sensing surface. Devices which sense the position of a pointing object on a sensing surface generally have the advantages of being simple to use, reliable, rugged, compact and easy to integrate with current computers and other computing devices.
Numerous types of input devices utilize a position sensing surface. Examples are provided in various patent references. For example, U.S. Pat. No. 3,886,311 to Rodgers et al. (May 27, 1975) discloses a writing pen for detecting a time varying electrostatic field produced by a writing tablet. U.S. Pat. No. 4,672,154, also to Rodgers et al. (June 9, 1987) discloses a cordless stylus which emits a directional electric field from the tip of a conductive pen cartridge sensed by a digitizer tablet having an X-Y coordinate system. U.S. Pat. No. 4,680,430 to Yoshikawa et al. (Jul. 14, 1987) discloses a tablet-like coordinate detecting apparatus including a resistive film for determining the coordinate position data of a point on a plane indicated by the touch of a finger tip or other load. U.S. Pat. No. 4,103,252 to Bobick (Jul. 25, 1978) discloses a position sensing tablet with electrodes located on the boundaries of a sensing region which detects a human touch by the change in capacitive charge caused by the touch which varies the time constant of an RC network which is part of an oscillator. U.S. Pat. No. 4,736,191 to Matzke (Apr. 5, 1988) discloses a touch activated control device comprising individual conductive plates wherein a user's touch on the dieleectric layer overlaying the plates is detected by individually charging and discharging each of the sectors in the plates in a sequential manner to determine the increased capacitance of the sector. U.S. Pat. No. 4,550,221 to Mabusth (Oct. 29, 1985) discloses a touch sensitive control device which translates touch location to output signals and which includes a substrate that supports first and second interleaved, closely spaced, non-overlapping conducting plates. U.S. Pat. No. 4,639,720 to Rympalski et al. (Jan. 27, 1987) discloses an electronic sketch pad which contains a graphics input pad having an array of transparent capacitive pixels, the capacitance characteristics of which are changed in response to the passing of a conductive tipped stylus over the surface of the pad. European Patent Publication 574,213 to Miller (filed Jul. 6, 1993, published Dec. 15, 1993) discloses a proximity sensor that includes a sensor matrix array which senses changes in capacitance between horizontal and vertical conductors connected to the position sensing pad to determine x, y & z position information).
Among recent additions to the position sensing pad art is U.S. Pat. No. 5,305,017 to Gerpheide (Apr. 19, 1994). The devices and methods of the Gerpheide patent include a touch sensitive input pad upon which a user conveniently inputs position information with a finger. In operation, the user's fingertip is brought in close proximity to the top surface of the position sensing surface of the touch sensitive pad. The device of the Gerpheide patent detects the position of the fingertip in the horizontal ("x") and vertical ("y") directions of the touch pad, as well as the finger's proximity in the z direction in relation to the sensing surface. A device with a relative position sensing surface which is primarily operated by the touch of an operator's finger is commonly called a touch pad. In addition to a finger, Gerpheide's and many other touch pads can also be operated by other conductive objects.
Touch pads detect a finger placed on or near the sensing surface and translate movement of the finger into corresponding movement of a cursor on a display screen. One advantage of using a touch pad as an input device is that space is conserved. More specifically, the touch pad can be fixed in place and an operator can still manipulate a cursor on a display screen. This characteristic is very important when space constraints are at a premium.
Specifically, with regard to touch pad technology, touch pads have been modified for additional user friendliness through the addition of feedback systems. Touch pads with tactile feedback systems were developed to assist an operator in determining through touch where the operator's finger is resting in relation to different touch pad regions. An example of tactile feedback is disclosed in co-owned, co-pending International Publication Number WO 9718546 to Gerpheide (filed Nov. 12, 1996, published May 22, 1997), herein incorporated by reference. The tactile feedback disclosed by Gerpheide includes a combination of textures and raised ridges on the pad surface to indicate programmable "button" portions which, when tapped, execute a function programmably assigned to that button.
Touch pads with auditory feedback were developed to assist an operator in determining when a portion of the touch pad has been selected. An example of auditory feedback is disclosed in co-owned, co-pending U.S. patent application Ser. No. 08/558,126 (Gerpheide, filed Nov. 13, 1995), herein incorporated by reference. The auditory feedback disclosed by Gerpheide includes a microprocessor using the PC speaker to emit a tone to indicate a selection has been made. However, as with the touch screen display system, this audible feedback is subject to the processor's response time, and may be slow.
Touch pads have also been adapted to perform additional functions by defining numeric or alphanumeric key pads on a portion of the surface of a touch pad. An example of an adaptable touch pad is disclosed in co-owned, co-pending U.S. patent application Ser. No. 08/923,677 (Glad, filed Sep. 4, 1997), herein incorporated by reference. More recently, touch pads have also been adapted by adding a stylus and pattern recognition software for recognizing signatures and handwriting such as that commercially sold by Advance Recognition Technologies, Inc. of Chattsworth, Calif., and CyberSIGN, Inc. of Santa Clara, Calif.
In addition to the many advantages provided by touch pads existing in the art, disadvantages also exist, both generally, as previously mentioned, and when existing touch pads are applied to particular applications. First, existing touch pads, even those with enter zones on the touch pad surface, require a combination of operator taps on the surface to send a "mouse button click" or "enter/select" command to the host computer. For example, a slow and hard, down-and-up tap motion of the finger is required by some touch pads to generate a "mouse button click" command. The appropriate timing and force for the taps of a given pad, although convenient and efficient for expert users, do take time to learn and can be confusing and even painful for novice users and even expert users on a new system. Furthermore, there are people who, because of physical limitation, are unable to perform the tap combinations required on existing touch pads, or the double-click combination required by existing mouse devices. Second, existing touch pads include many functions which are not needed in many simple applications such as in an information kiosk or other graphical interface. These additional functions may complicate touch pad operation and confuse an operator. Third, existing touch pads are not durable enough for many applications. Due to the thin plastic layer typically used to protect the sensing surface, touch pads may wear or deteriorate after extended or frequent use. Furthermore, the thin plastic layer typically used on the sensing surface of a touch pad may be insufficient to protect the surface from abrasive environments where kiosk systems are typically found such as industrial plants, restaurants, copy centers, hospitals, ATMs, and other environments where a touch pad will be used frequently by one person or frequently by numerous people such as in a library or other information center. Fourth, touch pads which are not completely sealed from external contamination may be inadequate for environments where dust, chemicals, moisture, or other contamination is prevalent, or risk of exposure to liquids is high.
It would be advantageous to have a touch pad which is simple to learn and use, includes only the functions necessary for a simple application such as a graphical user interface, is more durable and rugged than existing touch pads, can be completely sealed from external contamination, and is not subject to processor speed for providing audible feedback to inform an operator that a selection has been made.